Thread: Overlapping windows? in a Jframe?

Your code now draws to the graphics object of the content pane, but this doesn't ensure that it will be drawn. The standard way to paint to a JComponent (in your case the conentPane) is to override its paintComponent method. In your case you can create a new JPanel, over-ride its paintComponent method, then add that to the content pane

JPanel panel = new JPanel(){
    @Override public void paintComponent(Graphics g){
        super.paintComponent(g);
        g.setColor(Color.BLUE);
        g.drawRect(50,50,100,30);
    }
};
getConentPane().add(panel);

wait a second, i dont know where should i put that code in my program...

can you please add it so i can examine it carefully...

is it supposed to be like this?

public class Ch5SampleGraphics_UF  {
 
    public static void main(String[] args) {
 
        JFrame win;
        Container contentPane;
        Graphics gra;
 
        win = new JFrame("My First Rectangle");
        win.setSize(300, 200);
        win.setLocation(100, 100);
        win.setVisible(true);
 
        JPanel panel = new JPanel(){
 
            @Override public void paintComponent(Graphics g){
 
                super.paintComponent(g);
                g.setColor(Color.BLUE);
                g.drawRect(50,50,100,30);
            }
        };
 
        panel.setBackground(Color.red);
        contentPane = win.getContentPane();
        contentPane.add(panel);
 
        gra = contentPane.getGraphics();
        gra.setColor(Color.blue);
        gra.drawRect(50, 50, 100, 30);
    }
}

??

now the big question is??


why should i add a panel ... so the graphics can be drawn?

is the content pane not enough to make the drawing visible?

so when it comes in making a drawing in frame... i should declare a panel for it?

Like this

public class Ch5SampleGraphics_UF  {
 
    public static void main(String[] args) {
 
        JFrame win;
        Container contentPane;
        Graphics gra;
 
        win = new JFrame("My First Rectangle");
        win.setSize(300, 200);
        win.setLocation(100, 100);
        win.setVisible(true);//this line should be called AFTER things are added to the JFrame, otherwise you must valudate the JFrame, also remember its good practice to call pack()
 
        JPanel panel = new JPanel(){
 
            @Override public void paintComponent(Graphics g){
 
                super.paintComponent(g);
                g.setColor(Color.BLUE);
                g.drawRect(50,50,100,30);
            }
        };
 
        panel.setBackground(Color.red);
        contentPane = win.getContentPane();
        contentPane.add(panel);
        /**These lines do nothing   
        gra = contentPane.getGraphics();
        gra.setColor(Color.blue);
        gra.drawRect(50, 50, 100, 30);
        **/
 
    }
}

Originally Posted by chronoz13

now the big question is??


why should i add a panel ... so the graphics can be drawn?

is the content pane not enough to make the drawing visible?

so when it comes in making a drawing in frame... i should declare a panel for it?

The answer is a bit complex and has to do with how things are drawn in Swing. JComponents are drawn using paintComponent, so whenever a window is resized, scrolled, or altered in a way to necessitate redrawing, the paintComponent method is called to redraw the window. Just getting a reference to the Graphics object associated with a JComponent and drawing to it doesn't ensure that it will be drawn (or in more probable terms, erased by the parent paintComponent method next time it is redrawn)

ahhh so i was asking for a complex answer, hehhee, anyway.. you game me a little clarification of what i want...

tnx for that... sir!